The present invention relates generally to robotic manufacturing and in particular to apparatus and method for attaching a flexible circuit to a suspension used in the read/write head gimbal assembly of hard disk drives.
The hard disk drive is the device most predominantly used for long term memory storage in modern computer systems. In overview, a hard disk drive comprises a disk that is rotated at high speeds. The disk has a magnetic coating and selected areas of the coating can be magnetized with the application of a magnetic field. A xe2x80x9cread/writexe2x80x9d device, commonly called a head, is suspended above the disk and moved radially, that is, from the edge of the disk toward the center and back. Electric current is provided to the head which creates and applies a magnetic field to the disk as the head moves. Selective areas of the disk are preferentially magnetized as the magnetic field is applied to the disk. Each magnetized area consists of a north and south pole selectively oriented in one of two preferred directions. Magnetized areas having a north pole pointing in one of the two direction are designated as a xe2x80x9c0xe2x80x9d and in the other direction as a xe2x80x9c1.xe2x80x9d In this way the binary language of computers consisting of zeroes and ones is assembled and data and programs, which comprise zeroes and ones in binary computer language, are stored on the hard disk.
The hard disk provides large amounts of storage capability at relatively low cost. In addition, as the technology continually matures, the storage density per unit of cost, that is, the quantity of data stored per dollar, is continuously increasing, as is the reliability of the hard disk and its related components, (collectively called the hard disk drive, hard drive, or disk drive) and the rate at which data can be transferred to and from the disk. That is, advancing hard disk technology is resulting in the storage of increasing amounts of information at decreasing unit costs. Yet, in spite of the rapid advance in storage technology, the technology continues to face cost pressures as competition in the marketplace intensifies and computer programs grow in size.
An exploded view of a flex circuit/suspension assembly is shown in FIG. 6, which illustrates several components including a csuspension A and a flex circuit B. It will be understood that the actual physical structures of these components may vary in configuration. Typically, the suspension A will include a base plate C, a radius (spring region) D, a loadbeam E, and a gimbal F. At least one tooling aperture G may be included. The flex circuit B may include a base H, which may be a synthetic material such as a polyimide, that supports typically a plurality of electrical traces or leads I of the flex circuit. In addition, any of the surface features of the suspension A and the flex circuit B, such as the loadpoint J of the suspension A or the cure holes K of the flex circuit B, can be designated an optical target or an alignment target for use in the process of assembling the flex circuit and the suspension to each other. Additionally, the suspension A and/or flex circuit B may include fiducials that are specifically placed thereon for imaging purposes during an assembly operation.
The components shown in FIG. 6 as well as all those associated with hard disk drives are small and continually decreasing in size. Consequently, any tolerance for misalignment of the components during the assembly process is also continuously decreasing while their susceptibility to damage during assembly is increasing.
Current disk drive assembly includes expensive, labor intensive processes, particularly the assembly of the flex circuit to the suspension assembly. The labor intensive nature of the assembly process has several consequences. First, the labor increases the final cost of the assembled suspension. Second, because of the heavy use of labor in the assembly, there is a meaningful quantity of handling of the components by the assembler, which increases the likelihood of damage to the components. Third, the assemblers are limited in both the precision and speed with which the flex circuits can be assembled to the suspensions. Fourth, even though human assemblers are used, the assembly process is quite tooling intensive. Finally, as the part geometries change as the technology advances, the costs also increase because of the need for new tooling in the assembly of the new parts; that is, the tooling used is either not adaptable or not readily adaptable to new part geometries.
Additional costs that are not included in calculation of the cost of the use of human assemblers are those of the consumer whose hard drive fails, perhaps due to damage to a component by a human assembler. Though data backups are always advised, such advice is often unheeded. When a hard drive fails the consumer may lose valuable data that is either not easily replaced or is replaced only at some cost in terms of time and effort, if not actual cash outlays.
Many of the foregoing deficiencies in the employment of human assemblers could be reduced or eliminated with a precision automated assembly apparatus and method for attaching flex circuits to suspensions. Automated assembly machines and methods should result in lower costs, reduced component handling and possible damage, and have greater flexibility to accommodate variations in component types, geometries and improved placement tolerances.
It is an object of the present invention to provide new and improved apparatus and methods that are not subject to the foregoing disadvantages.
It is another object of the present invention to provide an apparatus that can be used for the automated assembly of one or more component parts of a read/write head gimbal assembly to each other.
It is still another object of the present invention to provide a method for the assembly of one or more component parts of a read/write head gimbal assembly to each other.
The foregoing objects of the present invention are provided by an assembly system employing at least a robotic or automated assembly apparatus to manipulate the components to be assembled and at least a first vision alignment system to align the components prior to their assembly. An adhesive dispense system is provided to connect, attach or otherwise adhere the components together.
In a method in accord with the present invention, a plurality of component parts are assembled to each other. A source of the component parts is provided and the source is located relative to a global or absolute reference system. The components held by the source are then located relative to the global reference system based upon the determined location of the source. An adhesive is dispensed onto a first of the components. A second component is manipulated into an initial attachment position relative to the first position and the components are imaged by a second or local imaging system to establish their position relative to each other. The second component will be manipulated relative to the first based upon their calculated relative positions to position the second component at the desired attachment position and then will be lowered into engagement with the adhesive and the first component. The adhesive may then be at least partially cured if desired.